Anti-condensation heating and dehumidifying method for power box body

Abstract

The invention relates to the technical field of electric power, in particular to an anti-condensation heating and dehumidifying method for an electric power box. Comprising the following steps: acquiring atmospheric humidity through weather forecast, and acquiring box humidity through a humidity sensor in a power box; when the state of the humidity sensor is normal, the PID heating strategy is controlled by the humidity of the box body; when the humidity sensor is damaged, the heating strategy is controlled through the atmospheric humidity. The invention provides a method for judging whether the state of a humidity sensor is abnormal or not under the condition that only the humidity sensor is used. Dehumidification and heating strategies are respectively formulated for the normal and abnormal states of the humidity sensor, and the stability of the power system is remarkably improved. When the humidity sensor is normal, the PID heating control strategy is adopted to quickly dehumidify under the condition of high humidity, and the dehumidification time is prolonged under the condition of low humidity, so that frequent start and stop of the heater are avoided.

Description

Technical Field

[0001] The invention relates to the field of electric power technology, and in particular to a method for heating and dehumidifying an electric box to prevent condensation. Background Art

[0002] The outdoor facilities of the power system are in a high humidity environment in the south for a long time, and condensation is inevitable. For some equipment, especially 220kV and above substations, condensation may cause safety hazards such as grounding and rust of the secondary circuit of the equipment in the box.

[0003] The most common way to solve the condensation problem is to install a heater in the box and turn on the heater to dehumidify when the humidity is too high. To implement this solution, a humidity sensor is currently installed in the box. When the data collected by the humidity sensor is higher than the threshold, the heater is automatically or remotely controlled to work.

[0004] Its major shortcomings are: 1. When the outdoor humidity is high for a long time, the heater will be frequently turned on and off, which may easily lead to heater failure; 2. When the humidity sensor is damaged, the power box cannot effectively dehumidify, causing safety hazards; 3. The heater heating strategy cannot be optimized for different humidity environments, resulting in too fast or ineffective dehumidification. Summary of the invention

[0005] The present invention discloses a method for heating and dehumidifying a power box to prevent condensation, which is characterized in that the specific method is as follows:

[0006] Obtain atmospheric humidity through weather forecast, and obtain cabinet humidity through humidity sensor in power cabinet;

[0007] If the atmospheric humidity is higher than the first threshold and the cabinet humidity is lower than the second threshold, or the cabinet humidity data is lost, it is determined that the cabinet humidity sensor is broken; at this time, the current condensation atmospheric humidity threshold is predicted, and when the atmospheric humidity is higher than the current condensation atmospheric humidity threshold, the first atmospheric humidity heating control strategy is enabled;

[0008] If the humidity in the cabinet is higher than the second threshold, the heater is started, and the heating power of the heater is controlled by a PID heating control algorithm.

[0009] The advantage of this embodiment is that, when only the humidity sensor is used, a method for determining whether the humidity sensor state is abnormal is provided. Dehumidification and heating strategies are formulated for the normal and abnormal states of the humidity sensor, respectively, which significantly increases the stability of the power system. When the humidity sensor is normal, the PID heating control strategy can be used to quickly dehumidify under high humidity conditions, and to extend the dehumidification time under low humidity conditions, thereby avoiding frequent starting and stopping of the heater.

[0010] Furthermore, the first threshold is the maximum condensation humidity of the atmosphere corresponding to the condensation of the power box within the calibration temperature range;

[0011] The second threshold is the value obtained by subtracting the maximum humidity deviation between the atmosphere and the power box when condensation occurs in the power box in a non-heating condition from the first threshold.

[0012] The advantage of this embodiment is that when the atmosphere is at the lowest condensation humidity, condensation will inevitably occur in the box without heating; if the humidity sensor has not reached the dehumidification start threshold, that is, the second threshold, then it is determined that the humidity sensor is damaged. The second threshold is determined by the maximum deviation between the atmospheric humidity and the box humidity when the box sealing effect is the best.

[0013] Furthermore, when the heater is controlled to heat by the PID heating control algorithm, if the change speed of the humidity in the box is less than the first speed threshold, it is determined that the box door is not closed, and a box door alarm is triggered;

[0014] When the heater is controlled to heat with the PID heating control algorithm, if the cabinet humidity change rate is less than the second speed threshold or the cabinet humidity is lost, it is determined that the humidity sensor is faulty and the first atmospheric humidity heating control strategy is enabled.

[0015] The advantage of this embodiment is that it provides a method for judging whether the door is closed only by relying on the humidity sensor, and a method for judging the failure of the humidity sensor by heating, thereby saving dehumidification costs.

[0016] Furthermore, when the box door is not closed after the last inspection and the humidity sensor is currently judged to be faulty, the second atmosphere heating control strategy is activated.

[0017] The advantage of this embodiment is that, for the case where the door is not closed and the humidity sensor fails, an independent heating control strategy is provided to distinguish the heating control strategy when the door is closed.

[0018] Furthermore, the first atmospheric humidity heating control strategy uses atmospheric humidity as a decision basis to control the heater heating, and the specific method is as follows:

[0019] The current ambient temperature is obtained, and the current atmospheric condensation humidity is determined according to the current ambient temperature. When the current atmospheric humidity is greater than the current atmospheric condensation humidity, the heater is started at the first power until the calibration time.

[0020] The advantage of this embodiment is that when the humidity sensor is damaged and the door is closed, heating is performed at a constant power for a fixed time, which can extend the heating time while ensuring the dehumidification effect and avoid frequent opening and closing of the heater.

[0021] Furthermore, the second atmospheric heating control strategy uses atmospheric humidity as a decision basis to control the heating of the heater, and the specific method is as follows:

[0022] The current ambient temperature is obtained, and the current atmospheric condensation humidity is determined according to the current ambient temperature. When the current atmospheric humidity is greater than the current atmospheric condensation humidity, the heater is started at a second power until the current atmospheric humidity is less than the current atmospheric condensation humidity.

[0023] The advantage of this embodiment is that when the humidity sensor is damaged and the door is not closed, condensation is particularly easy to occur, and continuous heating with a relatively low power is required to ensure the safety of the electrical equipment.

[0024] Furthermore, the current atmospheric condensation humidity is determined according to the current ambient temperature, and the specific method is as follows:

[0025] The current ambient temperature and the current time are used as inputs into a condensation humidity prediction model established for the power box, and the condensation humidity prediction model outputs the current atmospheric condensation humidity.

[0026] The advantage of this embodiment is that a condensation humidity prediction model is established for different ambient temperatures and different power box positions, which can improve the accuracy of the condensation humidity threshold and facilitate effective dehumidification.

[0027] Furthermore, the first power and calibration time are determined by an optimization algorithm, and the specific method is as follows:

[0028] Randomly generate a number of parameter combinations of different first powers and different calibration times;

[0029] Eliminate parameter combinations that cannot reduce the cabinet humidity below the target;

[0030] Determine the work and time required for the remaining parameter combinations to reduce the humidity of the box to below the target;

[0031] The fitness function is constructed with the least work done and the longest work time, and the parameter combinations ranked before the preset number are retained;

[0032] Taking the first power and calibration time corresponding to each reserved parameter combination as the center of the two-dimensional coordinate circle, setting a preset radius, and randomly generating a new parameter combination within the preset radius;

[0033] Repeatedly calculate the fitness function of the new parameter combination, screen and retain the new parameter combination, and randomly generate parameter combinations until the preset number of calculations is completed, and select the first power and calibration time parameter combination corresponding to the optimal fitness function as the final result.

[0034] The advantage of this embodiment is that, in the case where the door is closed and the humidity sensor fails, the heating time and heating power are optimized, the heating time is extended while the heating power is reduced, and energy is saved.

[0035] Furthermore, the second power determination method is as follows:

[0036] Determine the minimum heating power corresponding to different atmospheric humidity when the power box is not closed; when the heater is driven at the minimum heating power, the box humidity decreases at a preset speed;

[0037] Constructing a lookup table with different atmospheric humidity and corresponding minimum heating power;

[0038] The current second power is determined according to the current atmospheric condensation humidity and a lookup table.

[0039] The advantage of this embodiment is that, if the box door is not closed and the humidity sensor fails, low power consumption is used to ensure that there is no condensation in the box for a long time, thereby ensuring the safe operation of the power grid.

[0040] Furthermore, the heating power is controlled by a PID heating control algorithm, and the specific method is as follows:

[0041] Calculate the humidity deviation between the current cabinet humidity and the target humidity;

[0042] Use humidity deviation as feedforward input to control current heating power;

[0043] When the humidity deviation is less than the target deviation and the duration exceeds the time threshold, heating is stopped.

[0044] The advantage of this embodiment is that, when the humidity sensor is in a normal state, rapid dehumidification can be performed in the early stage to ensure the safety of the equipment, and low-power dehumidification can be performed in the later stage to extend the dehumidification time and prevent the heater from being frequently turned on and off.

[0045] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings of the present invention are as follows.

[0047] Figure 1 It is a schematic diagram of the overall process of the present invention.

[0048] Figure 2 This is a schematic diagram of the PID heating control process.

[0049] Figure 3 This is a schematic diagram of the first atmospheric humidity heating control strategy flow chart. DETAILED DESCRIPTION

[0050] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0051] A method for heating and dehumidifying a power box to prevent condensation, such as Figure 1 As shown, the specific steps are as follows:

[0052] S1. Obtain atmospheric humidity h through weather forecast a , obtain the box humidity h through the humidity sensor in the power box b .

[0053] S2: If the cabinet humidity is higher than the second threshold The heater is started and the heating power of the heater is controlled by a PID heating control algorithm.

[0054] Second threshold The first threshold Subtract the maximum humidity deviation Δh between the atmosphere and the box when the power box is condensed in the non-heating case max ,Right now First threshold It is the maximum condensation humidity of the atmosphere corresponding to the condensation of the power box within the calibration temperature range. The calibration temperature is the average ambient temperature range.

[0055] In step S2, when the PID heating control algorithm is used to control the heater to heat, if the humidity change rate of the cabinet is less than the first speed threshold It is determined that the door is not closed and the door alarm is activated.

[0056] When the PID heating control algorithm is used to control the heater heating, if the box humidity change rate is less than the second speed threshold Or the cabinet humidity is lost, it is judged as a humidity sensor failure, and the first atmospheric humidity heating control strategy is activated.

[0057] The heating power is controlled by PID heating control algorithm, such as Figure 2 As shown, the specific steps are as follows:

[0058] S21, calculating the humidity deviation e(t) between the current cabinet humidity and the target humidity;

[0059] S22, using humidity deviation as feedforward input to control the current heating power, the specific formula is as follows:

[0060] u(t)=kp*e(t)+ki*∫e(t)+kd*de(t) / dt

[0061] S23: When the humidity deviation is less than the target deviation and the duration exceeds the time threshold, stop heating.

[0062] S3. If the atmospheric humidity is higher than the first threshold And the cabinet humidity is lower than the second threshold Or when the cabinet humidity data is lost, it is judged that the cabinet humidity sensor is broken; at this time, the current condensation atmospheric humidity threshold th is predicted cc, when the atmospheric humidity is higher than the current condensation atmospheric humidity threshold, that is, h a >th cc , enable the first atmospheric humidity heating control strategy, such as Figure 3 shown.

[0063] In step S3, the first atmospheric humidity heating control strategy uses atmospheric humidity as a decision basis to control the heater heating. The specific method is: obtaining the current ambient temperature T, determining the current atmospheric condensation humidity th according to the current ambient temperature T cc , when the current atmospheric humidity is greater than the current atmospheric condensation humidity, that is, h a >th cc , start the heater with the first power p1 until the calibration time t1.

[0064] In step S3, the first power and calibration time are determined by an optimization algorithm, and the specific steps are as follows:

[0065] S31, randomly generate a number of parameter combinations {p1, t1} with different first powers and different calibration times;

[0066] S32, eliminating the parameter combination that cannot reduce the cabinet humidity to below the target;

[0067] S33, determining the work and work time required for the remaining parameter combinations to reduce the cabinet humidity to below the target;

[0068] S34, constructing a fitness function with the least work done and the longest work time, retaining the parameter combinations ranked before the preset number, the specific formula of the fitness function is as follows:

[0069]

[0070] Where a and b are preset weights.

[0071] S35, taking the first power and calibration time corresponding to each reserved parameter combination as the center of the two-dimensional coordinate circle, setting a preset radius, and randomly generating a new parameter combination within the preset radius;

[0072] S36, repeatedly calculating the fitness function of the new parameter combination, screening and retaining the new parameter combination, and randomly generating parameter combinations, until the preset number of calculations is completed, and selecting the first power and calibration time parameter combination corresponding to the optimal fitness function as the final result.

[0073] S4. When the door of the oven is not closed after the last inspection and the humidity sensor is currently judged to be faulty, the second atmosphere heating control strategy is activated.

[0074] In step S4, the second atmospheric heating control strategy uses atmospheric humidity as a decision basis to control the heater heating. The specific method is: obtaining the current ambient temperature T, determining the current atmospheric condensation humidity th according to the current ambient temperature T cc , when the current atmospheric humidity is greater than the current atmospheric condensation humidity, that is, h a >th cc , the heater is constantly started at the second power p2 until the current atmospheric humidity is lower than the current atmospheric condensation humidity.

[0075] In step S4, the second power determination step is as follows:

[0076] S41, determining the minimum heating power corresponding to different atmospheric humidity when the power box is not closed; when the heater is driven with the minimum heating power, the box humidity decreases at a preset speed;

[0077] S42, constructing a query table with different atmospheric humidity and corresponding minimum heating power;

[0078] S43: Determine the current second power according to the current atmospheric condensation humidity and a lookup table.

[0079] In steps S3 and S4, the current atmospheric condensation humidity is determined according to the current ambient temperature. The specific method is: the current ambient temperature and the current time are input into a condensation humidity prediction model established for the power box, and the condensation humidity prediction model outputs the current atmospheric condensation humidity.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for heating and dehumidifying a power box to prevent condensation, characterized in that: The specific method is as follows: Obtain atmospheric humidity through weather forecast, and obtain cabinet humidity through humidity sensor in power cabinet; If the atmospheric humidity is higher than the first threshold and the cabinet humidity is lower than the second threshold, or the cabinet humidity data is lost, it is determined that the cabinet humidity sensor is broken; at this time, the current condensation atmospheric humidity threshold is predicted, and when the atmospheric humidity is higher than the current condensation atmospheric humidity threshold, the first atmospheric humidity heating control strategy is enabled; If the humidity in the cabinet is higher than the second threshold, the heater is started, and the heating power of the heater is controlled by a PID heating control algorithm.

2. The anti-condensation heating and dehumidification method for a power box as claimed in claim 1, characterized in that: The first threshold is the maximum condensation humidity of the atmosphere corresponding to the condensation of the power box within the calibration temperature range; The second threshold is the value obtained by subtracting the maximum humidity deviation between the atmosphere and the power box when condensation occurs in the power box in a non-heating condition from the first threshold.

3. The anti-condensation heating and dehumidification method for a power box as claimed in claim 1, characterized in that: When the heater is controlled by the PID heating control algorithm to heat, if the change rate of the humidity in the box is less than the first speed threshold, it is determined that the box door is not closed, and the box door alarm is activated; When the heater is controlled to heat with the PID heating control algorithm, if the cabinet humidity change rate is less than the second speed threshold or the cabinet humidity is lost, it is determined that the humidity sensor is faulty and the first atmospheric humidity heating control strategy is enabled.

4. The anti-condensation heating and dehumidification method for a power box as claimed in claim 3, characterized in that: When the door has not been closed since the last inspection and the humidity sensor is currently judged to be faulty, the second atmosphere heating control strategy is enabled.

5. The anti-condensation heating and dehumidification method for a power box as claimed in claim 3, characterized in that: The first atmospheric humidity heating control strategy uses atmospheric humidity as a decision basis to control the heater heating, and the specific method is as follows: The current ambient temperature is obtained, and the current atmospheric condensation humidity is determined according to the current ambient temperature. When the current atmospheric humidity is greater than the current atmospheric condensation humidity, the heater is started at the first power until the calibration time.

6. The anti-condensation heating and dehumidification method for a power box as claimed in claim 4, characterized in that: The second atmospheric heating control strategy uses atmospheric humidity as a decision basis to control the heater heating, and the specific method is as follows: The current ambient temperature is obtained, and the current atmospheric condensation humidity is determined according to the current ambient temperature. When the current atmospheric humidity is greater than the current atmospheric condensation humidity, the heater is started at a second power until the current atmospheric humidity is less than the current atmospheric condensation humidity.

7. The anti-condensation heating and dehumidification method for a power box as claimed in claim 5 or 6, characterized in that: Determine the current atmospheric condensation humidity based on the current ambient temperature. The specific method is as follows: The current ambient temperature and the current time are used as inputs into a condensation humidity prediction model established for the power box, and the condensation humidity prediction model outputs the current atmospheric condensation humidity.

8. The anti-condensation heating and dehumidification method for a power box as claimed in claim 5, characterized in that: The first power and calibration time are determined by an optimization algorithm, and the specific method is as follows: Randomly generate a number of parameter combinations of different first powers and different calibration times; Eliminate parameter combinations that cannot reduce the cabinet humidity below the target; Determine the work and time required for the remaining parameter combinations to reduce the humidity of the box to below the target; The fitness function is constructed with the least work done and the longest work time, and the parameter combinations ranked before the preset number are retained; Taking the first power and calibration time corresponding to each reserved parameter combination as the center of the two-dimensional coordinate circle, setting a preset radius, and randomly generating a new parameter combination within the preset radius; Repeatedly calculate the fitness function of the new parameter combination, screen and retain the new parameter combination, and randomly generate parameter combinations until the preset number of calculations is completed, and select the first power and calibration time parameter combination corresponding to the optimal fitness function as the final result.

9. The anti-condensation heating and dehumidification method for a power box as claimed in claim 6, characterized in that: The second power determination method is as follows: Determine the minimum heating power corresponding to different atmospheric humidity when the power box is not closed; when the heater is driven at the minimum heating power, the box humidity decreases at a preset speed; Constructing a lookup table with different atmospheric humidity and corresponding minimum heating power; The current second power is determined according to the current atmospheric condensation humidity and a lookup table.

10. The anti-condensation heating and dehumidification method for a power box as claimed in claim 1, characterized in that: The heating power is controlled by the PID heating control algorithm. The specific method is as follows: Calculate the humidity deviation between the current cabinet humidity and the target humidity; Use humidity deviation as feedforward input to control current heating power; When the humidity deviation is less than the target deviation and the duration exceeds the time threshold, heating is stopped.

Images